In recent years, there has been increased activity in the development of mm-wave (millimeter wave) integrated circuits. There has also been an increased interest in systems on silicon, such as those related to monolithic integration in CMOS, as well as to relatively low cost related CMOS processes. This research has followed the aggressive scaling down of transistor size. In fact device fmax/fT has pushed high enough that CMOS processes can now be considered for a range of applications which had previously been completely dominated by the more exotic and expensive III-V compound semiconductor processes.
However, because of low manufacturing yields and the high economic costs of design and manufacture, integrating large numbers of transistors in silicon by use of existing process technologies remains problematic for high frequency circuits. Conservative designs, which have attempted to increase production yields by increasing design margins, have proven to be wasteful and inefficient solutions. Even more problematic are designs which include a RF power amplifier (PA), such as a high frequency (e.g. mm-wave) PA.
What is needed, therefore, is a new cost effective architecture which can increase high frequency integrated circuit production yields.